Humans are exceeding the bounds of natural systems and acting as "super-predators," a new report finds.
The analysis by researchers from the Raincoast Conservation Foundation, University of Victoria (UVic), and the Hakai Institute, and published in the journal Science, looked at over 300 studies that compared human hunter predation and that of non-humans. Whereas other predators are largely able to hunt at sustainable rates, humans, equipped with "with advanced killing technology and fossil fuel subsidy," are killing adult prey at a much higher—and unsustainable—rate.
"Our wickedly efficient killing technology, global economic systems, and resource management that prioritizes short-term benefits to humanity have given rise to the era of the human super predator," stated Dr. Chris Darimont, science director for Raincoast and Hakai-Raincoast professor at the UVic. "Our impacts are as extreme as our behavior as predators, and increasingly humanity bears the burden of our predatory dominance."
The analysis shows that globally, humans and non-humans kill herbivores at roughly the same rate. With respect to large carnivores, a clear difference emerges, with humans killing them at a rate 9 times that of non-human predators.
The contrast is particularly stunning when looking at fish, with human predation being 14 times that of non-humans.
Non-human predators generally target juveniles, while humans target adults, and that can have devastating impacts.
"In the overwhelming number of cases as fishes age, they become more fecund," Darimont explained. "That is to say, they produce more eggs, have more babies, and, in fact, in many cases, many of those babies are more likely to survive and reproduce themselves.
"So when a predator targets that reproductive age class and especially the larger more fecund animals in those populations, we are dialing back the reproductive capacity of populations," he stated.
"The implications that can result," the authors write, "are now increasingly costly to humanity and add new urgency to reconsidering the concept of sustainable exploitation."
It's no small fix to bring about the changes needed, researchers note.
"Transformation requires imposing limits of humanity’s own design: cultural, economic, and institutional changes as pronounced and widespread as those that provided the advantages humans developed over prey and competitors."
One way to impose such limits and work towards sustainability, the researchers write, is to make human predation rates more similar to those of non-humans.
Co-author Dr. Caroline Fox, postdoctoral fellow with Raincoast and the UVic, adds that the shift-change needed requires "cultivating appreciation for terrestrial carnivores and new approaches to exploitation in the oceans."
Without a shift to such sustainable practices, the authors write, humans "will continue to alter ecological and evolutionary processes globally."
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See more about the contrast in predation rates in the infographic below by the researchers: